Up to Nearly 3,100 Deaths Have Occurred on Mediterranean Sea Routes

ROME—More than 4,000 people have died world-wide so far this year while attempting to migrate, with the vast majority perishing while attempting to cross the Mediterranean, according to a report released Monday by the International Organization for Migration.

The Geneva-based group said that 4,077 migrants are known to have died since the start of the year. Up to 3,072 of those deaths occurred on dangerous routes across the...